1. Field of the Invention
The present invention relates to resin compositions, processes for their production, their uses, and their coated products.
2. Discussion of Background
In recent years, attention has been drawn to a resin composition comprising an organic silicon compound and various types of polymer including an acrylic resin, as a material having merits of both organic and inorganic natures. The resin composition comprising these components usually employs one or more organic solvents such as higher alcohols, ketones, esters or aromatic substances, in a substantial amount in order to attain compatibility among the components, storage stability of the liquid or good physical properties of the coating film thereby formed.
These organic solvents are likely to evaporate during coating and thus create a problem from the viewpoint of global environmental protection. Accordingly, there have been worldwide movements to restrict their uses. Especially when coating is applied to a metal, cement or various ceramic base materials, treatment at a relatively high temperature is required, whereby evaporation of solvents is likely to bring about a danger of inflammation, which adds to the problem. Accordingly, it is desired to develop a resin composition containing an organic silicon compound which employs an aqueous solvent and which contains at least 10 wt % of water. However, when an aqueous solvent is employed, the organic silicon compound is poor in compatibility with water in addition to inadequate affinity between the organic silicon compound and the organic polymer in a curable composition. Accordingly, the presence of an organic solvent in the aqueous solvent has been required, and it has been impossible to exclude an organic solvent. Further, the resin composition employing an aqueous solvent may sometimes undergo solidification during storage, and it has been difficult to practically use it.
As a method for producing a stable aqueous resin, JP-A-10-36514 discloses a technique wherein a polymer containing both hydrolyzable silyl groups and acid groups and a silicon compound having hydroxyl groups or hydrolyzable silyl groups, are subjected to a condensation reaction, followed by neutralization with a basic compound for stabilization. However, the physical properties of the coating film thereby obtainable, are not fully satisfactory, and further, depending upon the type of the silicon compound used, gelation is likely to result, and it has been difficult to obtain a stable liquid composition, or film forming has been difficult.